Vancouver’s Mayor Gregor Robertson has broken up with girlfriend Wanting Qu, the Vancouver-based pop star whose mother is facing corruption charges and a possible death penalty in China.

In response to a question about their relationship, the mayor’s office confirmed on Thursday that Robertson and Qu “are no longer together. They ended their relationship in May”.

Qu did not respond to a request for comment made via her Nettwerk music label. But after the SCMP reported the breakup online, she said on Twitter : “We wish nothing but happiness and success for each other and continue to be close friends. Love.”

Robertson, 52, and Qu, 33, went public with their relationship in January 2015, six months after the mayor announced his separation from his wife of more than 25 years, Amy Robertson.

In July 2016, it emerged that Qu’s mother, Qu Zhang Mingjie, a former civic official in the Chinese city of Harbin, was accused of embezzling 350 million yuan (US$52 million) in a complex real estate scam. Zhang denies the charges.

Prosecutors have asked for Zhang, 61, to be executed. However, the Harbin City Intermediate People’s Court has yet to issue a ruling in the case.

Last week Wanting Qu issued a brief statement on the Weibo social media platform saying she had confidence in a just outcome in the case, and that the court’s lengthy consideration suggested “ the court is handling the case very carefully, and the views of the defence are important”.

China’s courts have a 99.9 per cent conviction rate, according to the China Law Yearbook.

Qu and Robertson’s relationship has played out on social media, with the pop singer posting playful photos of the couple, and the pair swapping loving messages in public.

But neither Qu nor the mayor have publicly referenced their relationship in months.

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The Hongcouver blog is devoted to the hybrid culture of its namesake cities: Hong Kong and Vancouver. All story ideas and comments are welcome. Connect with me by email ian.young@scmp.com or on Twitter, @ianjamesyoung70.